CMSC 611: AdvancedCMSC 611: AdvancedComputer ArchitectureComputer ArchitectureCost, Performance & BenchmarkingCost, Performance & BenchmarkingSome material adapted from Mohamed Younis, UMBC CMSC 611 Spr 2003 course slidesSome material adapted from David Culler, UC Berkeley CS252, Spr 2002 course slides, © 2002 UC BerkeleySome material adapted from Hennessy & Patterson / © 2003 Elsevier ScienceOverviewOverview• Previous Lecture– What computer architecture– Why it is important to study– Organization and anatomy of computers– Impact of microelectronics technology oncomputers– Evolution and generations of the computer industry• This Lecture– Cost considerations in computer design– Why measuring performance is important– Different performance metrics– Performance comparisonTechnologyTrendsEvaluate ExistingEvaluate ExistingSystems for Systems for BottlenecksBottlenecksBenchmarksSimulate NewSimulate NewDesigns andDesigns andOrganizationsOrganizationsWorkloadsImplement NextImplement NextGeneration SystemGeneration SystemImplementationComplexitySlide: Dave PattersonCost and performance are the main evaluation metrics for a design qualityCost and performance are the main evaluation metrics for a design qualityComputer EngineeringComputer EngineeringMethodologyMethodologyCircuitsCircuits2,400,000Very large-scale integrated circuit1995900Integrated circuits197535Transistor19651Vacuum tube1951Relative performance/unit costTechnology used in computersYear• Need connectors & switches• Generation defined by switch technologyAdvances of the IC technology affect H/W and S/W design philosophyAdvances of the IC technology affect H/W and S/W design philosophyIntegrated CircuitsIntegrated Circuits• Start with silicon (found in sand)• Silicon does not conduct electricity well– thus semiconductor• Chemical process can transform tiny areas to– Excellent conductors of electricity (like copper)– Excellent insulator from electricity (like glass)– Areas that can conduct or insulate under a specialcondition (a switch)• A transistor is simply an on/off switchcontrolled by electricity• Integrated circuits combines dozens to millionsof transistors in a chipSlicer20 to 30processing stepsDicerDietesterBond dieto packageParttesterShip tocustomersPackaged diesTested packaged diesPatterned wafersIndividual dies(one wafer)Tested diesSilicon IngotBlank wafersMicroelectronics ProcessMicroelectronics ProcessSlice FabDiceTestPackageTestShip† IC Cost =Die Cost + Testing Cost +Packing CostFinal Test YieldSlide: Dave PattersonIntegrated Circuits CostsIntegrated Circuits Costs † Die Cost =Wafer CostDies per Wafer ¥ Die YieldDie cost roughly goeswith die area4Die cost roughly goeswith die area4† Dies per Wafer =p ¥ (Wafer diameter/2)2 Die Area-p ¥ Wafer diameter 2 ¥Die Area † Die Cost =Wafer CostDies per Wafer ¥ Die YieldSlide: Dave PattersonDie CostDie Cost† Die Yield = Wafer yield ¥ 11+Defects per unit area ¥ Die AreaaÈ Î Í Í Í Í ˘ ˚ ˙ ˙ ˙ ˙ a † Die Cost =Wafer CostDies per Wafer ¥ Die YieldFigure: Dave PattersonDie CostDie CostSlide: Dave PattersonReal World ExamplesReal World ExamplesDieCostYieldDies/WaferArea(mm2)Defect/cm2WafercostLayersChip$4179%402961.5$15003Pentium$27213%482341.6$17003SuperSPARC$14919%532341.2$15003DEC Alpha$7327%661961.0$13003HP PA 7100$5328%1151211.3$17004PowerPC 601$1254%181811.0$12003486DX2$471%360431.0$9002386DXFrom "Estimating IC Manufacturing Costs,” by Linley Gwennap,Microprocessor Report, August 2, 1993, p. 15Aside: Geometric ReasoningAside: Geometric Reasoning• Accelerate triangle rendering by dividingscreen into W 5 H pixel regions (processors)WHAside: Geometric ReasoningAside: Geometric Reasoning• Only render triangle in region hit bytriangle bounding box (size w 5 h)Aside: Geometric ReasoningAside: Geometric Reasoning• Triangle replicated for each regionoverlapping triangle bounding box– Like having N extra trianglesAside: Geometric ReasoningAside: Geometric Reasoning• Speedup limited by overlap factor– Distribution of box center vs. replication1x2x 2x2x2x4x 4x4x4x † Eyles formula :w + WWÊ Ë Á ˆ ¯ ˜ h+ HHÊ Ë Á ˆ ¯ ˜Costs and Trends in CostCosts and Trends in Cost• Understanding trends in componentcosts (how they will change over time) isan important issue for designers• Component prices drop over timewithout major improvements inmanufacturing technologyWhat Affects CostWhat Affects Cost1. Learning curve:• The more experience in manufacturing a component, thebetter the yield• In general, a chip, board or system with twice the yieldwill have half the cost.• The learning curve is different for different components,complicating new system design decisions2. Volume• Larger volume increases rate of learning curve andmanufacturing efficiency• Doubling the volume typically reduces cost by 10%3. Commodities• Essentially identical products sold by multiple vendors inlarge volumes• Foil the competition and drive the efficiency higher andthus the cost down$/DRAM chipA dollar in 1977 = $2.95 in 2001Cost/MB = $500 in 1997 = $0.35 in 2000 = $0.08 in 2001Demand exceeded supplyË slow price dropEach generation drops in price by a factor of 10 to 30 over its lifetimeCost Trends for DRAMCost Trends for DRAMIntel List price for 1000 units of the Pentium IIIPrice drop due to yield enhancementsCost Trends for ProcessorsCost Trends for ProcessorsComponent CostDirect Cost Gross Margin Average DiscountAvg. Selling PriceList Price15% to 33% 6% to 8%34% to 39%25% to 40%Slidei: Dave PattersonCost vs. PriceCost vs. Price• Component Cost– Raw material cost for the system’s building blocks• Direct Cost (add 25% to 40%)– recurring costs: labor, purchasing, scrap, warranty• Gross Margin (add 82% to 186%)– nonrecurring costs: R&D, marketing, sales, equipmentmaintenance, rental, financing cost, pretax profits, taxes• Average Discount (add 33% to 66%)– volume discounts and/or retailer markup0%20%40%60%80%100%Mini W/S PCAverage DiscountGross MarginDirect CostsComponent CostsSlide: Dave PattersonChip Area (mm2) Total Cost Price Comment 386DX 43 $9 $31 486DX2 81 $35 $245 NNoo CCoommppeettiittiioonn PowerPC 601 121 $77 $280 DEC Alpha 234 $202 $1231 Recoup R&D? Pentium 296 $473 $965 Chip Prices (August 1993) for a volume of 10,000 unitsExample: Price vs. CostExample: Price vs. CostThe Role of PerformanceThe Role of Performance•